As a description language capable of comprehensive handling three-dimensional information using the framework of the WWW (World Wide Web) providing various types of information on the Internet, that globally constructed computer network, the VRML (virtual reality modeling language) has been known.
First, an explanation will be given of the historical background up to the development of the VRML.
As an information system able to be used on the Internet, the WWW developed by the Swiss CERN (European Center for Nuclear Research) is known. The WWW was designed to enable text, images, sound, and other multimedia data to be viewed and heard by a hyper text format and asynchronously transfers to personal computers and other terminal equipment information stored in WWW servers based on protocol called HTTP (Hyper Text Transfer Protocol). The WWW is basically comprised of servers and browsers.
A WWW server is comprised of server software known as an HTTP daemon and HTML (Hyper Text Makeup Language) files storing hyper text information. A "daemon" is a program which manages and processes information in the background when working on UNIX.
Hyper text information is expressed by a description language called the HTML. Hyper text is described by HTML by the expression of the logical structure of sentences by format designations known as "tags" surrounded by "&lt;" and "&gt;". Links with other information are described by link information known as "anchors". When designating a location of information by anchors, a URL (Uniform Resource Locator) is used.
The protocol for transferring a file described in HTML on a TCP/IP (Transmission Control Protocol/Internet Protocol) network is HTTP. HTTP functions to send a request for transfer of information from a client to a WWW server and transfer hyper text information of an HTML file to the client.
A WWW browser is often used as the environment for uses of the WWW. "Browse" means to freely view. A browser executes the work for inquiring about information to a server in accordance with an operation of a user. A WWW browser is Netscape Navigator (trademark of Netscape Communications Corporation of the U.S.) and other client software. It is possible to use a WWW browser to browse through files, that is, home pages, of WWW servers on the globally expanding Internet, corresponding to a URL, and possible to successively follow back linked home pages to access various sources of information on the WWW--called "net surfing".
In recent years, the WWW has further expanded. Specifications for description languages for three-dimensional graphics, called VRML, have been formulated enabling description of three-dimensional spaces and setting hyper text links for objects drawn by three-dimensional graphics and enabling a user to successively access WWW servers while following back the links. VRML browsers are being developed for displaying three-dimensional spaces described based on such VRML specifications.
Details of VRML are described for example in the reference "VRML o Shiru: 3-Jigen Denno Kukan no Kochiku to Buraujingu (Learn About VRML: Building and Browsing Three-Dimensional Computer Space)", written by Mark Pesce, translated by Koichi Matsuda, Terunao Kamachi, Shoichi Takeuchi, Yasuaki Honda, Junichi Toshimoto, Masayuki Ishikawa, Ken Miyashita, and Kazuhiro Hara, first edition published Mar. 25, 1996, published by Prentis Hall, ISBN4-931356-37-0 (original work: "VRML: Browsing and Building Cyberspace", Mark Pesce, 1995 New Readers Publishing, ISBN 1-56205-498-8) and the reference "VRML no Saishin Doko to CyberPassage (Recent Trends in VRNL and CyberPassage)", Koichi Matsuda and Yasuaki Honda, bit (published by Kyoritsu)/1996, Vol. 28, No. 7, pp. 29 to 36, No. 8, pp. 57 to 65, No. 9, pp. 29 to 36, and No. 10, pp. 49 to 58).
The formal and complete specifications in "The Virtual Reality Modeling Language Version 2.0", ISO/IEC CD 14772, was pulished on Aug. 4, 1996.
As a VRML 2.0 browser and shared server software, for example, the present applicant, Sony Corporation, has developed and is marketing "Community Place (trademark) Browser/Bureau".
In the VRML 2.0, it is possible to describe and express autonomous behavior of an object in a three-dimensional virtual space. When using VRML 2.0 to prepare VRML content where an object moves around in a three-dimensional virtual space, normally the following process of work is undergone. Note that below the set of a VRML file, script file, etc. for realizing behaviors of a series of objects in a single virtual space is called "VRML content".
Routine for Preparing VRML Content
The general routine for preparing VRML content is described below.
(1) Preparation of Model
The shape, position, etc. of an object (model) arranged in a virtual space are described based on VRML 2.0 to prepare a basic VRML file.
(2) Description of Sensor Node
TouchSensors generating events in the case of click operation by a mouse (pointing operation) on objects in the virtual space, a TimeSensor generating an event when a predetermined time arrives, and other sensor nodes are added to the VRML file.
(3) Description of Routing
The description of the routing for transmission of events generated in accordance with pointing operations with respect to objects to which sensor nodes have been added is added to the VRML file.
(4) Description of Script Node
The description of a script node for transfer of events transmitted by the routing to and from an external script is added to the VRML file.
(5) Preparation of Script File
A script (program) in the Java language (Java is a trademark of Sun Microsystems of the U.S.) for realizing predetermined behavior for objects in the virtual space based on events transmitted through the script node is described to prepare a script file.
The desired VRML content is prepared by the process of description of the above (1) to (5).
When desiring to prepare VRNL content accompanying the autonomous behavior of an object in a virtual space based on VRML 2.0, an existing authoring software, called a modeler, for example, 3D Studio Max (trademark), or other software is used to prepare the shape of the object or animation and output the same in the VRML 2.0 format. When the modeler does not support the VRML 2.0 format, it is necessary to use a converter etc. to convert to the VRML 2.0 format.
Further, descriptions of various sensor nodes etc. defined by the VRML 2.0 are added to the VRML file using a text editor, scripts in the Java language are prepared using a text editor, corresponding script nodes are added, routes are added, etc. repeatedly.
Finally, when confirming the actual operation, a VRML browser compatible with VRML 2.0 is activated and the behavior of the object is confirmed by a click operation by a mouse etc.
This method of preparing VRML content features an extremely large amount of complicated work and remarkably poor work efficiency. For example, when adding a field to a script node, it is necessary to revise both the script file and the VRML file. Further, it is necessary to maintain a match between the two.
When designating routing of an event as well, further, it is necessary to ensure a match of the type of the event (format of data). If the format of description of the event etc. is mistaken, when reading by a VRML browser, a composition error will arise and it is necessary to again revise the file. Further, each time a node is added, re-reading by the VRML browser is necessary, so the work efficiency is extremely poor.
Points have been found in the performance of the interactive operation in the conventional method which should be improved. One example of a defect in the interaction is the trouble and inefficiency of the confirmation operation when preparing a world. FIG. 1 is a flow chart of the routine of a conventional method of preparation of a world. The production of the world is classified in two parts. In the first part, the model is produced according to steps S101 through S103. Details will be discussed later in comparison with embodiments of the present invention, but while confirmation is necessary when preparing a world, in the convention method of preparation shown in FIG. 1, as illustrated at step 108, it is necessary to use a browser.
Further, in the prior art, the improvement has been desired in the display and setting of the region (boundary line) of a sensor node of an object in three-dimensional virtual space.